Pedro, "adding a 2nd radial" must not be read as "adding a 2nd radiator", hi.So the existing 9.15m radiator (without 1:9 unun) with newly 2 radials of 4m each could be used as a vertical, inverted-L or inverted-V.

This antenna would then look very similar to my compact 60-10m vertical (inverted-L or -V) consisting of a 9.10m radiator, 4 radials of 4.20m each, fed through a common mode choke (photos). The antenna base is usually attached to the mast at about 0.5m over ground or, if the mast is fixed to a metallic structure, kept away some meters and fixed on a tent peg. This antenna connected to a KX3/ATU performs very well.

That's really interesting, Manuel! Great project! It would be interesting to also have some more compromised antennas tested and compared in the future as well. I recently bought a HF-P1 portable antenna especially for SOTA and WWFF activations. It's basically a clone of the well known Super Antenna MP-1. It's a vertical of about 2.5 meters in length and can be used from 80 to 10m HF. It's loaded with an adjustable coil and has 4 radial wires connected to its base. I'm sure it will not perform as well as the HyEndFed 10/20/40 EFHW wire antenna I normally use, but I bought the HF-P1 because it's much easier to carry and take up on a mountain, it's easier to set up, and with its tripod it's self-supporting (not always there's a structure available to strap the 10m fiberglass pole to for the EFHW)Would be interesting to see how the HF-P1 compares to the other antennas in a WSPR analyses as you presented here, especially on 40m. I've been making some CW QSOs at 5 Watt on 40m with the antenna in my garden surrounded by houses and other structures everywhere, so it does work, but what will the difference be compared to the other antennas?

Heinz, I am always impressed by the standard of your construction, and the nice touches like the BNC dust cover in this case. Seeing such things encourages me to raise my construction standards!

I have to ask you, what is the thinking behind three bolts to mount the BNC connector? In your case it cannot be an oversight, or saving the effort of drilling another hole! Of course three is mechanically sound, but the manufacturer has provided four holes.... Saving weight?

Re: "Dust protection"The cap for the BNC jack was added primarily as a protection against damage in the backpack.

Re: "Three mounting bolts"You almost guessed it, hi. First, this connector type was choosen because of its low installation height. Second, two screws would suffice from mechanical and electrical point of view but because for practical reasons the 2 screws (soldering lugs) for attaching the coax shield should be close to each other, a third screw was installed. Of course, from a purely cosmetic point of view, a fourth screw could be installed, hi.

Good work guys...this kind of real time comparison is really useful. Of course, all sorts of local anomalies can impact results; different aerial heights, different orientations, take off et al but this at least gives some sort of baseline empirical guide and with more people repeating the comparisons we should build up a useful indicator of 'real' performance.I was particularly impressed by the consistency of the vertical with one counterpoise. Looking a the lengths of the radiator and the counterpoise is this simply a random length wire mounted vertically?I'm inspired to try this one out...

I was particularly impressed by the consistency of the vertical with one counterpoise. Looking a the lengths of the radiator and the counterpoise is this simply a random length wire mounted vertically?

I guess one could look at it that way... The performance of this arrangement has impressed me as well, especially since the radial was lying in the grass and not elevated. What wasn't mentioned in the PDF is that the KX3 was placed right at the base of the pole, so the radiator wire coming down from the mast could be connected directly, without any balun or coax whatsoever. This may not always be convenient.